Gabriel's become accustomed to the chip in his head on Intelligence, but when a case hits home he begins to question it. In "Size Matters," malicious nanites are programmed to kill scientists. Will Gabriel and Riley be able to stop them before Cassidy is targeted?

Is Gabriel human or machine? He begins to question who he is now that he has the chip in his head. Check out two sneak peeks from "Size Matters."

Gordon Grayson is a target. When Gabriel starts looking into the man, Dr. Tyler gets curious about how Gabriel knows that information.

Dr. Tyler figures out that Gabriel is "special." Gabriel insists he's human, while Dr. Tyler wants him embrace what he is -- "the future."

Riley questions whether Gabriel let Dr. Tyler get under his skin. Gabriel wishes he didn't know all about her weekend, but she reminds him it's because he knows her. "It's not the chip."